This invention relates to hand held power cutting tools in general, and most particularly to hand held, power assisted pinking shears for cutting a serrated edge in cloth or other fabric material.
The use of a pinking shear to obtain a saw-tooth or zigzag border or line of severance when cutting cloth fabric is a well known expedient to eliminate unraveling of the yarn or thread along the edges of certain materials that would occur when a straight edge cut is provided. Power pinking cutters are known in the art which provide a serrated rotating blade acting in cooperation with an anvil or backing member, but these suffer from the problem of not being able to finely control the rate of feed of the fabric being cut, thus resulting in inaccurately cut cloth.
Previous manual pinking shears have the deficiency of hurting the hand of the user, since pinking shears require much more hand strength than ordinary shears. An object of this invention is to provide a pair of pinking shears that are powered by an external power source, eliminating the need for such hand strength and the accompanying pain and fatigue. This will be especially appreciated by those persons who sew that are afflicted with arthritis in their hands. The power shears of the present invention will not hurt the hand becauses they are pneumatic, being operated by air pressure. Another object of the present invention is to provide for a powered pinking shear that permits the user to obtain an accurate cut the first, thus eliminating the need to re-cut the serrated edge, which can lead to premature unraveling and defeat the entire purpose of using a pinking shear. The teeth of the blades of the pneumatic pinking shear of the present invention are curved to provide smooth cutting action and minimal blade wear. The blades could easily be programmed to be milled on a modern CNC machine. The teeth on the blades are wider than other pinking shears in order to improve the quality of the finished cut. This will decrease the amount of thread unraveling after the fabric is cut.
Another object of the present invention is to eliminate any potential source of electrical spark that may cause fire in an environment that would be filled with flammable materials such as in a tailor shop or garment factory.
Yet another object of the present invention is to provide for a quiet power pinking shear that eliminates much of the noise associated with power pinking shears of the prior art.